1) Field of the Invention
The present invention relates to an image forming apparatus, an image forming system, and an image forming operation control method, which can reduce peak power consumption when a plurality of image forming apparatus, which are connected to each other via a communication line, work in parallel.
2) Description of the Related Art
Sometimes many image forming apparatuses, which may be copying machines, are connected to each other via a communication line to form an image forming system. All the image forming apparatuses operate in parallel so that images can be formed at high-speed and in large quantity. Thus, such an image forming system increases productivity.
Japanese Patent Application Laid-open Publication No. H9-83696 discloses a conventional technique. The user requests a copy job from a master copying machine to a slave copying machine remote from the master copying machine. The master copying machine displays, on its display unit, identifiers of slave copying machines and paper sizes provided by each slave copying machine, so as to allow the user to select the slave copying machine to be requested.
However, since such image forming apparatuses start operation at the same time, the power consumption rises instantaneously. Particularly, the power consumption is the maximum at the time of starting and finishing printing, because, the parts are started and stopped to be driven at these timings. When all the image forming apparatuses start operation at the same time, it gives a great burden on the electric power infrastructure of, for example, the building in which the image forming system is installed.
One approach is to connect the slave copying machines in a daisy chain. Because of the daisy chain, the instructions, which is are sent by the master copying machine to the slave copying machines, to start the operation, is automatically delayed. However, since the delay is very small, and the operating speeds of the devices have increased considerably as the technology has advanced, the slave copying machines start the operation almost simultaneously. Thus, the daisy chain is also not a solution to the problem.